A network is a group of two or more nodes that are linked together. Flow control mechanisms in networks govern the transfer of data packets from a source node to a destination node. One type of network is a slotted-ring network, in which there are a fixed number of time slots (“slots”) rotating around a transmission medium in a circular (or ring) topology. The transmission medium carries packets within these slots from source nodes to destination nodes. A slot may be referred to as “available” if it is not carrying a valid packet, and may be referred to as “busy” if it is carrying a valid packet. A slotted-ring network is said to exhibit the characteristic of “spatial reuse” if after a destination node sinks a packet from a slot, that slot become available so that another node on the ring can inject a packet into that slot.
In a slotted-ring network, traffic already on the ring has priority over traffic entering the ring. A slotted-ring network may be referred to as in a “starvation” situation if one of the nodes n on the network repeatedly fails to inject a packet onto the ring because the ring is continually busy carrying packets past that node n. This situation could persist indefinitely and may prevent the node that is suffering from starvation from ever making forward progress.
Slotted-ring networks having spatial reuse that have been employed in local area networks (“LANs”) have implemented starvation management techniques that focus on maintaining fairness. Such fairness schemes ensure that the nodes on the ring network are allocated an equal amount of ring bandwidth.